Core



Jan. 31, 1928.

G. L. MATH ER CORE Fild Dec. 12, 1925 xinflating the air bag. v air bag 1s to stretchand condition the cord Patented Jan. 31, 1928. i' l GEORGE L.'MATHER, OF MILW'AUKEE, WISCONSIN, ASSIGNOR OFFICE.

ro miin :FISK R'UBBER COMPANY, OF CHICOPEE FALLS, MASSAQHUSETTS, A CORPORATION OF MASSA- CHUSETTS.

CORE.

Application filed December 12, 1925. Serial No. 75,052.

My invention relates to the manufacturc of pneumatic tire casings and more particularly to a core upon which cord tire casings may be built and cured.

According to the usual practice casings of this type are built upon a core or former, removed therefrom a pneumatic tube commonly called an air bag inserted in the casing and theV casing then cured ina suitable mold under internal pressure supplied by The purpose of the fabric of the carcass so that upon vulcanization the cords are properly positioned in the carcass. The life of the air bag is limited, the time and labor involved in removing the casing from the building core and inserting a bag therein substantial, and further expense is involved in inflating the bag during vulcanization.

It has been proposed to use a solid rubber core upon which the casing is both built and cured thus eliminating the above items .of expense incident to the, use of an air bag. With the core just described the necessary stretch is secured by solid core under heat and the use of core pads during the building Operation.

It is the object of my invention to provide an improved type of solidcore which'will climinate the use-of core pads and provide a better control of the degree of stretch applied to the casing.

In the accompanying drawings which illustrate one embodiment of. my invcntion.

Figur-e 1 .isa side elcvation of .my .improved core, parts being broken away 'to better illustrate the parts, i

Figur-e 2 is a section of the cui-ing element of the core, I

Figur-e 3 is a section on the line'3--3 of Figure l, and

Figure 4 is a fragmentary section similar` to Figure 3, but showing a modified form.

Referring to the drawings l designatcs the core generally. Asshown in Figures 1 and 3 the core comprises two elements vnamely a substantially solid rubber annular cui-ing element 2 and an annular Supporting ring 3. The element 2 which may be formed of the rubber compound or stock conventionally employed for air bags is shaped in its normal condition, as shown in Figure2, to conform substantially to thex inner conto substantially the expansion of the stretching the fabric.

tour of the casing to be curecl. A split 4 is formed in the core element 2 extending fromv the inner circumference of the annulus the center of the core, where a channel 5 is formed to prevent the split 4 extending deeper into the core during use. The second element of the core, 3, is formed of any suitable material such as' east, steel or iron and comprises an annular ring having wedge shaped portion 6 adapted to be nserted in the vSplit 4 of element 2, and projection 7 engaging the bases of the separated portions of the element 2. As shown in vFigure 3 the faces of projections form a continuation ofelemente2, but if desired they may be extended as shown at 8 in Figure 4 to form bead positioning means. The element 3 is preferably cut in sections as at 9, the sections being secured to anv suitable type of Chuck adapted to Collapse the sections. i y

The method of using the core is as follows. The ring 3 is expanded into the element 2 as shown in Figures 1 and 3, and the casing built t-herein in any Conventional manner.

As will be evident from Figure 3 the sides of the casmg so built are separated in substantlally the same manner as when core pads are used. The ring3 is then collapsed, the element 2 assuming the shape shown in Figure 2. It will be obvious that the removal of wedge 6 and the return of element 2 to substantially normal shape is analogous to thc rcmoval of the core pads in them'ethod prevfously discusscd. Bend rings are now applied as in conventioual practice, the head rings drawing 'the beads inwardly and The assembly is now placed in a suitablev meld and subjected to vulcanizing temperature, the expansion of the element 2 further stretching the fabric.

The degree of stretch applied to the cords of the casing may be varied within reasonable limits by increasing or decreasing'the wdth of wedge 6 at its base.

It will be evident that-my invention prowith ring 6 constitutes'a building core having all theadvantages of a solid rubber core rplus vseparable core pads and that' upon remov'alof the .ring 3 element 2 functions as a Curing core having all the advantages of a solid rubb'er core.

I claim:

1. In combination a collapsihle annular support heving n weolge shnped portion forming its outer periphery :ind provided with luteral projections at its base and :i solid rubber annular core element Split in the plane of the :mnulns from the inner periphery to snhstflntially the erosS-sectionnl center, mounted thereon with the Weclge portion ot' the support engaged in said split.

2. A core element eolnprising :i rubher annnlus stlbstnntielly solid in cross-section, Split in the plane of the nnnulus from its inner periphery to snbstantially the center of its cross-section.

3. A core element comprising a rubber annnlns snlistantially solid in cross-section, `Qplit in the plane of the nnnnlns from its inneiI periphery to shhstantinlly the center of its cross-section. ssiicl Split terminating in an n'nnular clninnel.

4. A eoreeleinent eoinprising a rubher annulus snbfstantially solid in cross-section,

shziped to conforin Snhstnntinlly to the interior of n pneinnntic tire ensing, :ind split in the plane of the nnnnlns from it4 inner periphery to snhstnntinlly the center of its' eroFs-seetion.

A core element eoi'nrn'ising n rnhher :innnlns, enlistnntinlly solifl in eroJ-'e` section, shapetl to eontorin snhstizmt'inlly to the interior of u pnennintie tire nntl nrlnptetl to he (letiorinetl to hring the hetul and sidewnll engnging portions into tlesiretl position for building the tire enrcnss.

(3. A core element eoniprising :in annulns ot tleforninlale material shziped to conforni s-:nlvstant'inlly to the interior of n pneuinflt-ie tire ensingr antl :ulnpted to leie, Lleforlnecl to hring the heml nntl sitlewall engnging portzions` into (lesiretl position for building the tlre earcn'ss.

In testin'ion)Y whereot I heve signed my name to the. above speeiiention.

GEORGE L. MATl-IER. 

